The story of Prontosil and its related compounds intertwined during the first few decades of the 20th century with the story of penicillin, although the contrasts between the developments of these two antibacterial drugs are striking. Penicillin was discovered entirely by accident rather than by the methodical trial and error process leading to Prontosil. Alexander Fleming's discovery of penicillin was preceded by another discovery, that of lysozyme. Due to its importance in medicine, the story of penicillin's discovery has become shrouded in legend and distorted truths. Fleming gave the substance in his "mould broth filtrate" the name penicillin in a manuscript he prepared for British Journal of Experimental Pathology, deriving it from the name of the mold. A part of the Prontosil molecule, sulfanilamide, was an effective antimicrobial agent itself. Prontosil broke down in an animal (or human) body to derivatives; one was sulfanilamide, which was toxic to bacteria. With the entry of the United States into World War II, the U.S. government took over penicillin production, which rapidly escalated. The adoration in the media and the distorted truths about penicillin's discovery did not endear Fleming to the members of the Oxford team. The introduction of penicillin into clinical practice led to the modern antibiotic era, with the discovery in the 1940s and 1950s of many drugs that were isolated from other microorganisms. Fleming devised experiments to study antiseptics’ action on bacteria and on white blood cells.

6. Clutterbuck, P. W.,, R.Lovell, and, H.Raistrick. 1932. The formation from glucose by members of the Penicillium chrysogenum series of a pigment, an alkali-soluble protein and penicillin—the antibacterial substance of Fleming. Biochem. J. 26:1907–1918.